The present invention is related electron devices. In particular, electron devices including a non-evaporation-type getter and methods for manufacturing the electron devices.
Conventional electron devices, such as fluorescent luminous tubes, include hermetic envelopes (containers). A fluorescent luminous tube, which uses a non-evaporation getter (i.e. non-evaporation getter materials) applied on a black matrix formed on an anode substrate to absorb gases inside the vacuum envelope, has been proposed (for example, refer to Japanese Laid-open Patent publication No. Tokkai 2001-351510).
A conventional fluorescent luminous tube having non-evaporation getters will be explained below by referring to the fluorescent luminous tube of FIG. 8, which is a field emission display (FED) using field emission-type cathodes. In FIG. 8, FIG. 8(a) is a front view illustrating the field emission display viewed from an anode substrate side, and FIG. 8(b) is a cross-sectional view illustrating the field emission display taken along line X1-X1.
The field emission display has a vacuum envelope (container) which is formed of an anode substrate 11 and a cathode substrate 12. The anode substrate 11 and cathode substrate 12 are bonded together with seal glass pieces (side members) 13. Anodes 21, each in which a fluorescent substance is coated on an anode electrode, are formed over the anode substrate 11. A black matrix 22 is formed over the anode substrate 11, except anodes 21. Field emission cathodes 31 are formed over the cathode substrate 12.
Non-evaporation getter materials, such as chemical compounds of Ti or Zr, are mixed in the black matrix 22. In order to form the black matrix 22, an aqueous solution (carbon aqueous solution) is coated onto the anode substrate 11 and then the anode substrate is heated in the atmosphere at 545° C. The carbon aqueous solution is prepared by adding non-evaporation getter materials of a particle diameter of 1 μm or less into aqueous solution containing a glass series adhesive agent or binder (containing chiefly carbon).
Conventional non-evaporation getter materials having a particle diameter of about 1 μm have been used sparingly. However, the particle size, particle shape, and processing temperature, suitable for the getter, have not been disclosed. For example, when non-evaporation-type materials are mixed in the black matrix to form a getter, the non-evaporation materials are heated at about 545° C. during the black matrix forming process. The non-evaporation getter material, for example, ZrV, reacts chemically with gases most actively at a temperature of about 320° C. (hereinafter referred to as activation temperature). While being mixed in the black matrix, non-evaporation getter materials will absorb a large volume of gases through the chemical reaction. For that reason, when the vacuum envelope is sealed and evacuated, the active surface of the getter material is in a reduced state and in a gas absorption completion state. The getter in the vacuum envelope remarkably reduces its gas absorbing ability when gases absorbed on the envelope wall are sputtered out with electron rays. As a result, the black matrix reduces the getter capability. Since TiO2, or a non-evaporation getter material, is white, mixing a large volume of TiO2 leads to reducing the effect of the black matrix whereas a small volume of TiO2 leads to reducing the getter effect.